The present invention relates generally to controls and more specifically to communication between control devices or nodes connected in a network. Networks were traditionally used in large computer systems where the communication protocols were designed and optimized for large amounts of data between computers. The declining cost of microprocessors eventually allowed their use in inexpensive controllers and control devices. However, the communication protocols used in large data processing systems did not meet the unique requirements of control networks which typically require frequent communication between devices, short message formats, peer to peer communication and costs consistent with the use of low cost control devices. These requirements lead to the development of protocols designed for use in control networks rather than for use in data processing networks. The applications that use such control networks are many and varied. For example, the controls may be related to heating ventilating and air conditioning (HVAC) applications, lighting control applications, building security applications and many other applications. The present invention is not limited by the nature of the application. Many control manufacturers make control devices that communicate using a particular communication technology, one example of a communication technology is the LonWorks System as provided by the Echelon Corporation. In the simplest installation the control node is typically connected to a single control device in a stand-alone installation. In larger more complex installations a single Supervisory node may send messages to a number of Client nodes and the Client nodes may send messages to the Supervisory node as well as to other Client nodes. In order to initially establish this communication between a Supervisory node and a Client node, it typically requires a technician trained in the use of network tools or configuration tools to be physically present at the network installation site and to assign addresses to the nodes to allow communications between nodes and to configure the nodes. A network installation tool maintains a database of the device addresses for the network assigns the device addresses. Device addresses typically consist of three components: a domain address or ID, subnet ID, and node ID. Therefore, a technician trained in the use of the configuration tool will need to travel to the location of the network installation, coordinate the visit with the availability of other trade persons, e.g. an electrician, at the location and spend time at the location in performing the address assignment and configuration tasks. Depending on how the communication technology is implemented, these tasks may further require visiting each node location to set dip switches or to depress a button as part of the process. In addition to the technician tasks related to simply establishing communication between the nodes there are additional technician tasks. For example, many control nodes can also be configured to be capable of communication and interaction with multiple other nodes of similar design, providing system control and sharing of selected information through the system using a communication technique called xe2x80x9cbindingxe2x80x9d. Establishing these relationships between nodes is also accomplished with a configuration tool at the installation site.
The processes just described obviously increases the cost of a network installation.
Self-configuration has been proposed in the past but is usually limited to a very small subset of information and does not meet the need of self-configuration for control networks. Thus a need exists for a network system that will be automatically self configured.
The present invention solves these and other needs by providing in a first aspect a system of controllers acting as nodes on a network and providing automatic self-configuration. One controller is identified as a supervisory node and the remaining controllers are identified as client nodes with the supervisory node and each client node broadcasting a default identifier in a default domain. The default identifiers are created at the time of manufacture of the node microprocessor. The default identifiers from the client nodes are received and ranked according to a characteristic in the identifier at the supervisory node. A network address is created at the supervisory node for each client node and broadcast in the default domain to all client nodes. The client nodes receive all network addresses but only recognize and internalize the network address corresponding to a specific client node. Control information is then communicated between nodes utilizing subnet and node addressing.